In the electrophotographic copy process, copy paper is fed from a paper bin to a transfer station where the copy paper is mated with a surface carrying a developed electrostatic image of the original. At the transfer station, the electrostatic image is transferred to the copy paper and thereupon the copy paper is stripped away from the imagebearing surface. One of the problems of providing a reliable electrophotographic machine is the problem of reliably stripping copy paper from the image-bearing surface. Factors creating difficulty in stripping paper include the fact that the paper bears an electrostatic attraction to the image-bearing surface and therefore is to an extent electrically mated with that surface.
Many prior art electrophotographic machines utilize rotating drums as the image-bearing surface. If the copy paper is not stripped away from the drum, the paper wraps itself around the drum and creates a situation which generally requires the services of a specially trained repairman. Various types of strippers are found in the prior art including the provision of indentations in the drum surface at the leading edge of the copy paper so that gaseous fluid can be blown into the indentations at the proper time in order to create forces which push the paper away from the drum. Other detacking mechanisms used in the prior art include mechanical bars which ride on the surface of the drum and peel the paper away from the drum when the paper reaches the peeler bar. The first solution has difficulties which include the fact that indentations have to be placed in the drum, which include the fact that the paper has to be positioned directly over the indentations, and which include the expense of air-blowing machinery. The mechanical peeler bar solution has drawbacks in that it rides on the drum surface and tends to mar the area of the surface of the drum with which it is in contact. Consequently, it is generally required to lower the peeler bar to the surface of the drum for a short period of time and then remove it. Once again, therefore, it requires timing to place the peeler bar on the surface of the drum at the right instant to coact with the arrival of the copy paper. It is, therefore, the primary object of this invention to avoid the cost and the timing problems of the prior art solutions and provide a simple, cheap, reliable solution to stripping paper from the drum of an electrophotographic machine.